Nowadays, power socket devices are widely used in daily life and working, wherein the power socket device can be plugged by a plug of an external appliance to transmit and supply an electric power thereto. Traditional, an external appliance has a plug to be electrically connected to the power socket device. After a user uses the external appliance, the user generally unplugs the plug from the power socket device for saving the power. However, the unplugging operation is inconvenient for most of users, so that it is difficult to completely carry out the unplugging operation every time. Furthermore, when repeating to connect/disconnect the plug with/from the power socket device after long-term use, an abrasion will be easily generated between the plug and the power socket device, so as to affect the lift time of the plug and/or the power socket device. Moreover, when the plug is inserted into the power socket device in a case that the external appliance is turned on, a spark will be generated between the plug and the power socket device due to over-current during the plug is transiently in contact with the power socket device, so that the metal of a contact portion therebetween will be heated, melt and deformed. Even, the lift time of internal components in the external appliance will be lowered. As a result, the traditional plugs must be frequently unplugged, so as to cause the inconvenience and the life time of the external appliance will be easily lowered.